1. Field of the Invention
The present invention relates to flight simulators and flight simulator controls. More particularly, the present invention relates to a linear flight simulator control loading system that linearly adjusts a control load to more realistically simulate an aircraft in flight.
2. Description of Prior Art
Many aircraft use mechanical linkages to connect a control to one or more control surfaces. The control may be a yoke or rudder pedals and allow a pilot to manipulate the control surfaces, such as, ailerons, elevators, and rudders. An aileron is typically mounted on a wing of an aircraft and is used to control roll of the aircraft. An elevator is typically mounted on a tail section of an aircraft and is used to control pitch of the aircraft. A rudder is typically mounted on a tail section of an aircraft and is used to control yaw of the aircraft.
These control surfaces function by deflecting airflowing past them. For instance, as air flows past a wing, an aileron can be rotated such that it deflects the air upward, therefore pushing the wing down. As the wing is pushed down, the aircraft rolls toward that wing.
Air flows past a control surface of an aircraft at a rate determined by, among other things, airspeed of the aircraft. As the aircraft moves faster, relative to the air it is moving through, the air flows past the control surface at a faster rate.
A common flight characteristic is, as air flows past a control surface at a faster rate, more force is required to manipulate the control surface. This force is typically referred to as control load. At a relatively low airspeed, a control surface requires relatively little force to rotate it to a fully deflected position. At a relatively high airspeed, the control surface requires greater force to rotate it to the fully deflected position.
This flight characteristic has proven difficult to efficiently, and realistically simulate, as part of a flight simulator. Current systems fall into one of two categories, complicated and sophisticated high cost systems and less sophisticated low cost systems.
High cost systems typically use hydraulics with a closed loop control scheme to simulate control load forces. These systems are complex, typically have many moving parts, and are subject to high maintenance requirements. Complexity, cost, and maintenance requirements prevent these systems from being used in all but the most expensive flight simulators.
Low cost systems typically use friction or simple springs to simulate control load forces. These systems are simple but not realistic. These systems typically have no way to adjust the force according to airspeed or other factors. Since they cannot realistically simulate control load, these systems can only be used in very rudimentary flight simulators.
Accordingly, there is a need for an improved flight simulator control loading system that overcomes the limitations of the prior art.
The linear flight simulator control loading system of the present invention overcomes the above-identified problems and provides a distinct advance in the art of flight simulator control loading systems. More particularly the present invention provides a linear flight simulator control loading system for use in a flight simulator that linearly adjusts a control load to more realistically simulate an aircraft in flight with a relatively inexpensive and simple construction that may be used in flight simulators of any cost.
The flight simulator typically includes a computer that interacts with a pilot and other components of the flight simulator. The pilot manipulates one or more controls, such as, a yoke and rudder pedals. The computer monitors the control position and commands the flight simulator in order to interpret the pilot""s actions and accurately simulate flight.
The preferred flight simulator control loading system broadly comprises a gearbox housing, a compression assembly, a tension assembly, and a shaft running through the assemblies and the gearbox housing. The gearbox housing includes a motor operable to rotate the shaft via a worm gear.
The compression assembly is connected to a control manipulated by a pilot and includes an outer housing, a guide housing, a fixed force actuator, an adjustable force actuator, a first spring, and a second spring. The outer housing slides along the guide housing which is fixedly secured to the gearbox housing. The force actuator is fixedly secured to the outer housing near a distal end. The adjustable actuator is slidably mounted within the guide housing near a proximal end. The adjustable actuator is allowed to slide but not rotate within the guide housing. The two springs are located between and push against the two actuators.
The tension assembly is typically connected to a trim system. The trim system is another component of the flight simulator that simulates another flight characteristic. The tension assembly is similar to the compression assembly and also includes an outer housing, a guide housing, a fixed force actuator, an adjustable force actuator, a first spring, and a second spring. The outer housing slides along the guide housing which is fixedly secured to the gearbox housing. The fixed actuator is fixedly secured to the outer housing near a proximal end. The adjustable actuator is slidably mounted within the guide housing near a distal end. The adjustable actuator is allowed to slide but not rotate within the guide housing. The two springs are located between and push against the two actuators.
The shaft runs through the springs and the actuators. The shaft is rotatably secured to each fixed actuator and threaded within each adjustable actuator. As the shaft is rotated in an increase direction, each adjustable actuator slides toward the respective fixed actuator, thereby compressing the springs and increasing control load. As the shaft is rotated in a decrease direction, each adjustable actuator slides away from the respective fixed actuator, thereby relieving compression on the springs and decreasing control load. The increase direction and the decrease direction are determined by the threads on the shaft and each adjustable actuator.
In use, the computer monitors factors such as airspeed and orientation of the aircraft being simulated and determines an appropriate control load level. When the computer determines that control load should be increased it causes the motor to rotate the shaft in the increase direction, thereby compressing the springs and increasing the force needed to move the control. Alternatively, when the computer determines that control load should be decreased it causes the motor to rotate the shaft in the decrease direction, thereby relieving compression on the springs and decreasing the force needed to move the control. As a pilot manipulates the control, he or she experiences more or less control load, just as in a real aircraft.